Merge pull request #1085 from msperl/rpi-4.0.y-spi-bcm2835-dma

spi-bcm2835: merge upstream patches allowing DMA transfers

Author: pelwell

arch/arm/boot/dts/overlays/Makefile

@@ -43,6 +43,7 @@ dtb-$(RPI_DT_OVERLAYS) += rpi-sense-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += sdhost-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += spi-bcm2708-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += spi-bcm2835-overlay.dtb
+dtb-$(RPI_DT_OVERLAYS) += spi-dma-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += tinylcd35-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += uart1-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += vga666-overlay.dtb

arch/arm/boot/dts/overlays/README

@@ -474,6 +474,12 @@ Load:   dtoverlay=spi-bcm2835
 Params: <None>
 
 
+Name:   spi-dma
+Info:   enables dma modes for spi-bcm2835
+Load:   dtoverlay=spi-dma
+Params: <None>
+
+
 Name:   tinylcd35
 Info:   3.5" Color TFT Display by www.tinylcd.com
         Options: Touch, RTC, keypad

arch/arm/boot/dts/overlays/spi-dma-overlay.dts

@@ -0,0 +1,20 @@
+/*
+ * Device tree overlay for spi-bcm2835 to allow dma
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2835", "brcm,bcm2836", "brcm,bcm2708", "brcm,bcm2709";
+
+	fragment@0 {
+		target = <&spi0>;
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			dmas = <&dma 6>, <&dma 7>;
+			dma-names = "tx", "rx";
+		};
+	};
+ };